23 lines
558 B
Text
23 lines
558 B
Text
import logic data.prod
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set_option pp.notation false
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inductive C [class] (A : Type) :=
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mk : A → C A
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definition val {A : Type} (c : C A) : A :=
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C.rec (λa, a) c
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constant magic (A : Type) : A
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definition C_magic [instance] [priority std.priority.max] (A : Type) : C A :=
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C.mk (magic A)
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definition C_prop [instance] : C Prop :=
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C.mk true
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definition C_prod [instance] {A B : Type} (Ha : C A) (Hb : C B) : C (prod A B) :=
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C.mk (pair (val Ha) (val Hb))
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-- C_magic will be used because it has max priority
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definition test : C (prod Prop Prop) := _
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eval test
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